SSC Sample Paper Mock Test-1 SSC CGL Tear-II Paper-1

  • question_answer
                           The value of\[\frac{\sin \,\,(x+y)-2sinx+\sin \,\,(x-y)}{\cos \,\,(x+y)-2\cos x+\cos (x-y)}\]is

    A)  \[\cot x\]                      

    B)  \[\tan x\]

    C)  \[\sin x\]                       

    D)  \[\text{cosec}\,\,x\]

    Correct Answer: B

    Solution :

    \[\frac{\sin \,\,(x+y)-2sin\,\,x+sin\,\,(x-y)}{\cos \,\,(x+y)-2\cos x+\cos \,\,(x-y)}\] \[=\frac{2\sin \frac{x+y+x-y}{2}\cdot \cos \frac{x+y-x+y}{2}-2\sin x}{2\cos \frac{(x+y+x-y)}{2}\cdot \cos \frac{(x+y-x+y)}{2}-2\cos x}\] \[=\frac{2\sin x\cos y-2\sin x}{2\cos x\cos y-2\cos x}=\frac{2\sin x(\cos y-1)}{2\cos x(\cos y-1)}\]\[=\frac{\sin x}{\cos x}=\tan x\]


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